Metal rectifier



T. J. HENRY ET AL June 30, 1936.

METAL RECTIFIER Filed April 15, 1935 WN SNN REW Y my E Nimm m ES. O vVASmmm n, OL A HU lil Patented June 30, 1936 UNETED STATES PATENT OEFFICEMETAL RECTIFIER Application April 13, 1935, Serial No. 16,126

6 Claims.

Our invention relates to electron discharge devices of the all-metaltype and more particularly to rectiiiers with metal envelopes.

Electron discharge all-metal rectiiiers of the all-metal type with along or pencil-shaped metal cylinder of small diameter used as the anodeas well as the envelope of the rectifier, have been suggested, but areapt to overheat when cooled by exposure only to the air, and aredangerous at high voltages if the high potential anode is exposed.

An object of our invention is to provide an eficient metal typerectifier of the air cooled type which will carry commercially desirableamounts of current without overheating.

A further object of our invention is the provision of a metal typerectier inexpensive to manufacture, rugged in construction and with highpotential exposed metal parts insulated and shielded.

A fuller understanding of our invention may be had by referring to theaccompanying drawing in which Figure 1 shows an elevation of one form ofour improved tube; Figure 2 shows a sectional view along lines 2--2 ofFigure 1; Figure 3 is a cut-away View of one of the rectifier elements;Figure 4 is a section along lines 4-4 of Figure l; Figure 5 is adetailed View of a modified iorm of the mount supporting means; andFigure 6 shows a slightly modified anode construction.

As best shown in Figure Sithe rectier element comprises an oblong orpencil-shaped cylinder l of relatively great length and small -diameterwhich in the embodiment illustrated functions as an envelope as well asan anode. Internally of the cylinder is a thermionic cathode 2,preferably of the indirectly heated type and having an elongatedcylindrical sleeve positioned coaxial with the anode cylinder byinsulating spacers 3, which preferably are polygonal in outline toreduce the contact area and heat conduction between the spacer andanode. The lower end of the anode cylinder is closed and the cathode iscarried by a plug or stem, such as a metal sleeve.

4, attached at one end, as by welding, to the inside of the anodecylinder, and carrying heater leads for the cathode, sealed into andinsulated from sleeve ll by a glass bead 5. At the upper end of theanode is a metal exhaust tube 6, thru which the envelope may beevacuated by an exhaust pump. The envelope may be evacuated to anydesired degree of pressure and may be either highly evacuated or filledwith gas at a low pressure. The exhaust tube 6 may be sealed off bypinching the tube together and then welding or .anode formed by thecurved portions.

(Cl. Z50-27.5)

brazing the tube walls at the pinch. Close spacing between the anode andcathode is obtained over an extended area of the cooperating surfaces ofthe anode and cathode, which results in low inter-electrode impedancewith a correspondingly high current carrying capacity.

in one Yorrn of our invention the anodeenvelope is constructed of twostrips 5 and 'l of sheet metal pressed into the form best shown intransverse section in Figure 4. Each of the metal strips 6 -and l isshaped, by pressing or by drawing in a die, into a sheet having two ilatrectangular portions lying in one plane with an intermediate curved orsemi-cylindrical portion as shown. The two shaped strips are placed faceto face with the flat rectangular portions of the two strips adjoiningeach other and with the intermediate curved portions in registry to forman enclosure. The flat portions are then welded or brazed together toform a gas-tight joint between them throughout their length. The joinedportions of the strips thus provide an extended sealing area between thestrips as Well as an effective heat radiator for cooling ns for theShould a more extensive radiating surface be found desirable ornecessary the flat portion of the metal strips B and l may be made widerand turned or bent outwardly beyond the joint as shown at 8 and 9. Suchextensions provide considerable `radiating surface in a minimum space.

As shown in Figure 6, the cylindrical anode may, if desired, be formed,from one sheet of metal and with only one welded joint, with a radialiin by rolling a single sheet of metal so that opposite edges of thesheet may lie parallel for sealing.

These forms of anode construction are characterized by the ease andaccuracy with which the anodes may be manufactured to a given irl--ternal diameter as well as by the simple yet efficient arrangement ofheat radiating fins.

As best shown in Figures l and 4, two rectifier units l and 2 aremounted side by side and 'are spaced apart top and bottom by insulatingstrip members l l and l 2 clamped to the units by straps I3 and i4. Theends of insulating members l l and l 2 are extended and so shaped as tofit inside a lprotecting shield or can l5, hereinafter more fullydescribed. Strips l I and l2 may be grooved, as shown at I6, to increasethe length of the leakage paths between the two high potential anodes ofthe units l and 2.

The two rectifier units l and 2 are conveniently supported upon a basemember I 'l by support rods I8 and I9, which are suitably secured as bywelding or brazing to the cooling ns of the rectifier units, as bestshown at 2G and 2l, The lower ends of the supports i8 and i9 may be bentand inserted in the upper end of the tubular contact pins of the base,and thus serve both as supports and anode leads. The cathode heaterleads of the two rectier units may be connected in series or parallel asdesired and connected to other pins in the base member.

To protect the parts of the rectifier from damage as well as to enclosethe high voltage units I and 2, the shell or cup-shaped sleeve member Iis lowered over the mount assembly and suitably secured at its lower endto the base. The base as shown is formed with a ilange or ledge 22against which the lower end of the enclosing shell I5 may abut.Enclosing shell I5 is preferably perforated to allow the freecirculation of air about the radiating iins of the rectier units. Theventilation ducts of the shieldingrcan I5 may take any desired iorm suchas uniformly spaced perforations over the side walls and tcp of theshell. Or, louvres and openings may be stamped out in the side walls andtop of the can, as shown at 2li, 25, their position being chosen topromote the natural circulation of air along the radiating i'lns. Withopenings at the top and bottom, as shown, a natural draft or chimneyeffect may be obtained.

In the modification shown in Figure 5 a second form or electrode mountsupporting means is shown. Strap members 353, SI are split at theirupper ends to permit their welding or brazing to the inner surface ofthe lower ends of the radiating ins. At the lower end of the straps areformed integral extensions 32, 33, which are bent to be welded orotherwise suitably secured to base pins in the base member. In thisconstruction the wide footing of the supporting straps upon the basemember afords rigid lateral support for the mount assembly.

It will be obvious to those skilled in the art that many modications maybe made in our device without departing from the scope of the invention.It is accordingly desired that our invention be limited only by theprior art and by the accompanying claims.

We claim:

l. An electron discharge device comprising an anode comprising anelongated metallic cylinder sealed in a gas-tight manner at its ends, anelectron emitting cathode positioned interiorly of said cylinder, a basemember with contact pins, means for supporting said anode upon andsubstantially normal to the plane of said base member, and protectingmeans for said anode comprising a perforate sleeve at least as long assaid anode iitted over saidanode and secured at one end to said basemember and held in spaced relation to said anode by an insulating spacermember.

2. An electron discharge device comprising two envelope units eachcomprising a hermetically sealed length of metal tubing containing anelectron emitting electrode, insulating spacers at each end of saidunits for securing said units in fixed parallel spaced relation, a basewith Contact pins, means for supporting said units upon said base, aperforated shell positioned over said units in engagement with saidinsulating spacers and secured at one end to said base, and electricalconnections between each of said metal tubings and contact pins in saidbase.

3. In combination, an anode electrode comprising an upright elongatedgastight metal container, an electron emitting cathode insulatinglysupported within said anode and connected with current leads sealed in agas-tight manner in the lower end of said container, a base with contactpins supporting said anode electrode, a shield comprising a sleevepositioned over and insulatingly spaced from said anode electrode andsecured to said base, said shield being perforated adjacent each end ofthe container to induce the circulation oi` air about said container,and electrical connections between said contact pins and the anodeelectrode and the cathode current leads.

4. A rectifier comprising a pencil-shaped anode-envelope comprising twoelongated strips of metal each with a longitudinal groove joined withthe grooves'in registry by a gas-tight seal along the edges of saidgrooves, the portions of said strips outward from said seal being bentat an angle to a plane thru the center line of said envelope to formheat radiating iins, an electron emitting electrode insulatinglysupported within the enclosure formed by said grooved strips, meansengaging the anode at each end or theV enclosure to hermetically sealthe enclosure, and current leads to said electrode insulatingly sealedin said envelope.

5. An electron discharge device comprising an evacuated sheet metalenvelope comprising two similar sheet metal members each with twoparallel flat portions lying in the same plane and an intermediatecurved portion oirset from said plane, the flat portions ci each memberadjoining the ilat portions of the other member with the intermediateportions of said members in registry to form an enclosure, said flatportions adjacent the curved portion being joined gas tight throughouttheir length, and edge portions outward from the gas tight joint toserve as heat radiators, a thermionic cathode mounted coaxially withinthe envelope and cathode leads insulatingly sealed thru a .glass bead inone end of said envelope and an exhaust tube sealed in the other end ofsaid envelope.

6. An evacuated envelope for an electron discharge device comprising twosimilar sheet metal members each with two flat rectangular portions inone plane and an intermediate semi-cylindrical portion, the flatrectangular portions of each member adjoining the corresponding iiatportions of the other member with the intermediate portions of saidmembers in registry to form an enclosure, said flat portions beingjoined gas tight throughout their length, a cathode centrally supportedin the envelope and an insulating plug in one end of said envelopecontaining leads ,for said cathode, a metal exhaust tube fitted into theother end of said envelope and supporting means for said envelope.

THOMAS J. HENRY. JULIUS HRMANN.

